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Irreversibilities in Propulsion Systems. P M V Subbarao Professor Mechanical Engineering Department. A Major Criteria for Geometric Design of Components…. Inlet. 7h. 4. 5. 6. 1. 7c. 2. 3. Irreversible Turbofan Cycle : Unwanted Entropy Generation. Inlet. 7h. 4. 5. 6. 1. 7c. 2.
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Irreversibilities in Propulsion Systems P M V Subbarao Professor Mechanical Engineering Department A Major Criteria for Geometric Design of Components…..
Inlet 7h 4 5 6 1 7c 2 3 Irreversible Turbofan Cycle : Unwanted Entropy Generation
Inlet 7h 4 5 6 1 7c 2 3 Irreversible Turbofan Cycle : Unwanted Pressure Loss
Classification of Irreversibilities • Internal Irreversibilities : Friction, flow separation & Turbulence • External Irreversibilities: Shocks, Friction, flow separation & Turbulence • Heat loss & incomplete combustion
External Flow Irreversibilities in Subsonic Intakes SupercriticalDesign
Normal Shock Intakes A sharp lipped subsonic diffuser may be used in supersonic engine without a significant aerodynamic penalty for Mac < 1.6.
Selection of Subsonic Diffuser with NS The total pressure recovery of a normal shock rapidly deteriorates beyond Mach ~ 1.6. 90% total pressure recovery is achieved at 1.6.
External Compression Inlets M>1 Oblique Shock Normal Shock Cowl Shock A single compression ram inlet involves one oblique shock and one normal shock.
Location of Oblique shock & External Drag No Slippage but High External drag Slippage with low External drag